import sys
#TODO: dodać parentices
class AbstractInterpreter:
    def __init__(self):
        pass
    def isValid(formula:str)->bool:
        raise NotImplementedError
class SimpleInterpreter(AbstractInterpreter):
    def __init__(self):
        pass
    def isValid(self,formula)->bool:
        print("is valid?")
        variables = {}
        f=[]
        def isBlacklisted(char):
            return char in ['\n', '\t', ' ']
        def isSign(char):
            logic_signs = ['=', '>', '&', '|', '!', '(', ')']
            return char in logic_signs
        def isVariable(char):
            return  not isSign(char) 
        def isNegation(char):
            return char == '!'
        #print(vars(formula))
        for i,char in enumerate(formula.s):
            if isBlacklisted(char): return False
            print(char)
            prev = formula.s[i-1] if i>0 else None #None, gdy jesteśmy na pierwszym znaku
            if isSign(char):
                if (not isNegation(char)):
                    if isSign(prev) and not isNegation(prev): # tylko negacje mogą się powtarzać po innym znaku
                        return False
                else:
                    if isVariable(prev): # obrona przed a!>b
                        return False
            else:
                 #if current char is a variable
                 if isVariable(prev) and prev is not None: #Obrona abc>d
                     print("previous is also a variable");
                     return False
        return True
class Formula:
    def __init__(self, formula_string:str, interpreter:AbstractInterpreter):
        self.s = formula_string
        self.__i = interpreter
        if not self.isValid(self.__i):
            assert "formula in invalid!"
        else:
            print("given formula is valid")
    def isValid(self, interpreter)->bool:
        
        return interpreter.isValid(self)


i = SimpleInterpreter()
print(sys.argv)
if sys.argv[1] == '-f':
    #open from file
    print("opening from file")
    g = open(sys.argv[1], 'r')
    u = g.readlines()
    for l in u:
        Formula(l,i)
else:
    Formula( sys.argv[1],i)